dj sets + lyrics: a mix that names its own tracks, and words pulled off the separated voice

crates/metadata/src/lib.rs

@@ -4500,6 +4500,27 @@ impl MetadataClient {
         }
     }
 
+    /// One catalog track by ISRC — the anchor-exact lookup for rows whose
+    /// identity came from AUDIO RECOGNITION (the recognizer reports the
+    /// matched release's ISRC). An id-grade identity, never a name guess;
+    /// `None` is an honest "that release isn't in the catalog".
+    pub async fn catalog_track_by_isrc(&self, isrc: &str) -> Option<CatalogTrack> {
+        let clean: String = isrc
+            .chars()
+            .filter(|c| c.is_ascii_alphanumeric())
+            .map(|c| c.to_ascii_uppercase())
+            .collect();
+        // ISRCs are exactly 12 characters (CC-XXX-YY-NNNNN without the
+        // dashes); anything else would only ever be a malformed URL.
+        if clean.len() != 12 {
+            return None;
+        }
+        let body = self
+            .deezer(&format!("https://api.deezer.com/track/isrc:{clean}"))
+            .await?;
+        parse_track(&body)
+    }
+
     /// The two things the search hero can say about an artist that Deezer
     /// cannot: what they sound like, and how big they are.
     ///